
package org.zhou.myrule;

import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.Server;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;


public class zhouRandomRule extends AbstractLoadBalancerRule {

    /**
     * Randomly choose from all living servers
     * 每个机器访问五次  换下一个服务
     * 首先得有一个total 默认为0  如果等于5 我们指向下一个服务节点
     * index 默认0 如果total=5那么index加一  如果index大于三 那么index归零 切total归0
     *
     */
    private int total=0; //被调用的次数
    private int currentIndex=0; //当前是谁在提供服务
    public Server choose(ILoadBalancer lb, Object key) {
        if (lb == null) {
            return null;
        }
        Server server = null;

        while (server == null) {
            if (Thread.interrupted()) {
                return null;
            }
            List<Server> upList = lb.getReachableServers();   //获得所有存活的服务
            List<Server> allList = lb.getAllServers();       //获取全部的服务

            int serverCount = allList.size();
            if (serverCount == 0) {

                return null;
            }

//            int index = chooseRandomInt(serverCount); //生成区间随机数
//            server = upList.get(index);  //从存活的服务中 随机获取一个
//          重写算法
            if (total<5){
                 server = upList.get(currentIndex);
                total++;
            }else {
                total=0;
                currentIndex++;
                if (currentIndex>upList.size()){
                    currentIndex=0;
                }
                 server = upList.get(currentIndex);//从活着的服务中获取指定的服务来进行操作
            }



            if (server == null) {

                Thread.yield();
                continue;
            }

            if (server.isAlive()) {
                return (server);
            }

            server = null;
            Thread.yield();
        }

        return server;

    }

    protected int chooseRandomInt(int serverCount) {
        return ThreadLocalRandom.current().nextInt(serverCount);
    }

	@Override
	public Server choose(Object key) {
		return choose(getLoadBalancer(), key);
	}

	@Override
	public void initWithNiwsConfig(IClientConfig clientConfig) {
		// TODO Auto-generated method stub

	}
}
